232 Notice of Messrs', Foster and Whitney^s Report 



The formation of this island was attended with earthquakes 

 and water-spouts, and the effusion of vast quantities of steam 

 and vapor. The surrounding water was covered with scorise 

 and the bodies of fishes. Fragments of rock were detached by 

 the waves and currents, and deposited in the bottom of the sea. 



Now, if its bed were laid bare, it would probably be found to 

 exhibit a section somewhat like the following : 



1. A mass of volcanic rock, forming an axis or cone, crystal- 



line or granular in proportion to the rapidity or slowness with 



which it parted with its heat^ and the degree of pressure to 

 which it had been subjected. 



2. Volcanic breccia, consisting of fragments which had be- 

 come detached and afterwards reunited with the fluid mass. 



3. Coarse conglomerate, composed for the most part of peb- 

 bles derived from the upheaved mass. 



4. Beds of arenaceous and calcareous particles, brought down 

 by the rivers of the adjacent coastj and enveloping the remains 

 of fishes, if not too perishable in their nature, and of shells, in- 

 habiting the surrounding sea. 



The conglomerates and trap tuffs would rapidly thin out as we 

 receded from the volcanic focus, and be replaced by the silts and 

 sediments derived from^ the rivers flowing into the sea. 



Such, we conceive, was the process by which the rocks em- 

 braced in this report were formed. The heated condition of the 

 fluids, as well as the gaseous exhalations constantly escaping 

 through the open fissures, would prevent the development of ani- 

 mal and vegetable life. 



When the igneous action became dormant, the water, having 

 parted with a portion of its heat, would absorb carbonic acid 

 from the atmosphere, which, uniting with the lime held in solu- 

 tion, would be precipitated in beds and layers at the bottom of 

 the sea. This Humboldt conjectures to have been the origin of 

 the vast deposits forming the Silurian limestones. As the condi- 

 tion of the water changed, the numerous types of animal Hfe 

 sprang into being, whose remains are so profusely scattered 



% 



throughout the strata of that era." 



There can be no doubt, judging from the known effects of 

 igneous action, that the authors are correct in representing the 

 conglomerate as a result attendant upon the igneous ejections. 

 The action of the waters of the ocean on a lava stream was ex- 

 hibited on a grand scale at the eruption of Kilauea, (Hawaii) in 

 1840, where the fused rock on reaching the sea, as Mr. Coan states, 

 *' was shivered like melted glass into millions of particles, which 

 were thrown up in clouds that darkened the sky and fell like a 

 storm of hail over the surrounding country," and as a result three 

 conical elevations were thrown up in a few days, the smallest 150 



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